When manufacturing semiconductor devices, usually a plurality of chips is manufactured on a single wafer. For example, typical semiconductor wafers used as substrates in a manufacturing process may have a diameter of 100 mm or more, e.g., 300 mm or more, and typical chip dimensions may be in the order of 100 μm up to some millimeters. Therefore, a plurality of chips can be formed on a single wafer, increasing manufacturing yield.
In such a manufacturing process, prior to obtaining the final product the chips on the wafer have to be separated from each other, resulting in a plurality of chip dies, also simply referred to as dies. These dies may then, for example, be individually packaged and contacted electrically to obtain final products.
In particular, with thin wafers having a metallization on at least one side thereof the quality of this separation sometimes is critical. For example, with some conventional separation processes fine cracks may occur in side walls of the individual chip dies which may later lead to reliability problems. Also, for example, when mechanical sawing techniques are used for separation, broad kerfs or scribe lines, typically of the order of 70 μm, are required due to a width of the sawing blade. Such mechanical sawing may also lead to crack formation.
On the other hand, when chip separation is performed using so-called plasma dicing, the metallization of the wafer may cause problems. In particular, metallizations often comprise a stack of different metals which may require the use of different etchants in addition to plasma dicing applied to semiconductor material of the substrate, thus making the process difficult.
In the following, embodiments will be described in detail referring to the attached drawings. The embodiments shown in the drawings or described herein are to be seen as examples only and are not to be construed as limiting the scope of the present application, as other embodiments may be implemented in other ways than shown without departing from the scope of this application. For example, describing an embodiment with a plurality of features is not to be construed as indicating that all such features are essential for implementing embodiments. Instead, in other embodiments, some features may be omitted, features may be replaced by alternative features and/or features may be added. Also, features may be arranged in a different temporal or spatial order compared to the one shown. Features of different embodiments may be combined with each other unless noted otherwise.